VictoriaMetrics/lib/promscrape/discovery/kuma/kuma.go
Aliaksandr Valialkin 1b70238dca
lib/promscrape/discovery/kuma: follow-up for 317fef95f9
- Do not generate __meta_server label, since it is unavailable in Prometheus.
- Add a link to https://docs.victoriametrics.com/sd_configs.html#kuma_sd_configs to docs/CHANGELOG.md,
  so users could click it and read the docs without the need to search the corresponding docs.
- Remove kumaTarget struct, since it is easier generating labels for discovered targets
  directly from the response returned by Kuma. This simplifies the code.
- Store the generated labels for discovered targets inside atomic.Value. This allows reading them
  from concurrent goroutines without the need to use mutex.
- Use synchronouse requests to Kuma instead of long polling, since there is a little sense
  in the long polling when the Kuma server may return 304 Not Modified response every -promscrape.kumaSDCheckInterval.
- Remove -promscrape.kuma.waitTime command-line flag, since it is no longer needed when long polling isn't used.
- Set default value for -promscrape.kumaSDCheckInterval to 30s in order to be consistent with Prometheus.
- Remove unnecessary indirections for string literals, which are used only once, in order to improve code readability.
- Remove unused fields from discoveryRequest and discoveryResponse.
- Update tests.
- Document why fetch_timeout and refresh_interval options are missing in kuma_sd_config.
- Add docs to discoveryutils.RequestCallback and discoveryutils.ResponseCallback,
  since these are public types.

Side notes: it is weird that Prometheus implementation for kuma_sd_configs sets `instance` label,
since usually this label is set by the Prometheus itself to __address__ after the relabeling phase.
See https://www.robustperception.io/life-of-a-label/

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3389

See https://github.com/prometheus/prometheus/issues/7919
and https://github.com/prometheus/prometheus/pull/8844
as a reference implementation in Prometheus
2023-02-22 17:50:54 -08:00

55 lines
1.8 KiB
Go

package kuma
import (
"flag"
"fmt"
"time"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/promauth"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/promutils"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/proxy"
)
// SDCheckInterval defines interval for targets refresh.
var SDCheckInterval = flag.Duration("promscrape.kumaSDCheckInterval", 30*time.Second, "Interval for checking for changes in kuma service discovery. "+
"This works only if kuma_sd_configs is configured in '-promscrape.config' file. "+
"See https://docs.victoriametrics.com/sd_configs.html#kuma_sd_configs for details")
// SDConfig represents service discovery config for Kuma Service Mesh.
//
// See https://prometheus.io/docs/prometheus/latest/configuration/configuration/#kuma_sd_config
type SDConfig struct {
Server string `yaml:"server"`
HTTPClientConfig promauth.HTTPClientConfig `yaml:",inline"`
ProxyURL *proxy.URL `yaml:"proxy_url,omitempty"`
ProxyClientConfig promauth.ProxyClientConfig `yaml:",inline"`
// fetch_timeout isn't used, so it isn't defined.
// FetchTimeout time.Duration `yaml:"fetch_timeout,omitempty"`
// refresh_interval is obtained from `-promscrape.kumaSDCheckInterval` command-line option.
// RefreshInterval time.Duration `yaml:"refresh_interval,omitempty"`
}
// GetLabels returns kuma service discovery labels according to sdc.
func (sdc *SDConfig) GetLabels(baseDir string) ([]*promutils.Labels, error) {
cfg, err := getAPIConfig(sdc, baseDir)
if err != nil {
return nil, fmt.Errorf("cannot get API config for kuma_sd: %w", err)
}
v := cfg.labels.Load()
pLabels := v.(*[]*promutils.Labels)
return *pLabels, nil
}
// MustStop stops further usage for sdc.
func (sdc *SDConfig) MustStop() {
v := configMap.Delete(sdc)
if v != nil {
// v can be nil if GetLabels wasn't called yet.
cfg := v.(*apiConfig)
cfg.mustStop()
}
}